The spectrum of GJB2 mutations in the Iranian population with non-syndromic hearing loss-A twelve year study

Objective: Mutations in GJB2, encoding connexin 26 (CX26), are causally related to autosomal recessive form of non-syndromic hearing loss (NSHL) at the DFNB1 locus and autosomal dominant NSHL at the DFNA3 locus. In this study, we investigated the prevalence of GJB2 mutations in the Iranian deaf population. Methods: A total of 2322 deaf probands presenting the ethnically diverse Iranian population were screened for variants in GJB2. All persons were first screened for the c.35deIG mutation, as this variant is the most prevalent GJB2-deafness causing mutation in the Iranian population. In all persons carrying zero or one c.35deIG allele, exons 1 and 2 were then sequenced. Results: In total, 374 (similar to 16%) families segregated GJB2-related deafness caused by 45 different mutations and 5 novel variants. The c.35deIG mutation was most commonly identified and accounts for similar to 65% of the GJB2 mutations found in population studied. Conclusion: Our data also show that there is a gradual decrease in the frequency of the c.35deIG mutation and of GJB2-related deafness in general in a dine across Iran extending from the northwest to southeast. (C) 2012 Elsevier Ireland Ltd. All rights reserved.